67Ga lung scan. An aid in the differential diagnosis of pulmonary embolism and pneumonitis.

Twenty-three patients patients with clinical signs of pulmonary embolic disease and lung infiltrates were studied to determine the value of gallium citrate Ga 67 lung scan in differentiating embolic from inflammatory lung disease. In 11 patients without angiographically proved embolism, only seven had corresponding ventilation-perfusion defects compatible with inflammatory disease. In seven of these 11 patients, the gallium 67 concentration indicated inflammatory disease. In the 12 patients with angiographically proved embolic disease, six had corresponding ventilation-perfusion defects compatible with inflammatory disease. None had an accumulation of 67Ga in the area of pulmonary infiltrate. Thus, ventilation-perfusion lung scans are of limited value when lung infiltrates are present. In contrast, the accumulation of 67Ga in the lung indicates an inflammatory process. Gallium imaging can help select those patients with lung infiltrates who need angiography.